Telephone-transmitter mouthpiece.



E. c. MUELLER, JR. TELEPHONE TRANSMITTER MOUTHIIECE. APPLICATIUII FILED FEB. 26, 1917.

1,252,475. Patented Jan. 8,1918.

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UNiTnn sTATns PATENT onnron.

EMIL C. MUELLER, J' R., OF ELIZABETH, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION 0F NEW YORK'.

TELEPHONE-TRANSMITTER MOUTHPIECE.

Specification of Letters Patent.

Patented Jan. 8,1918.

Application filed February 26, 1917. Serial No. 151,009.

To all whom t may concern.'

Be it known that I, EMIL C. MUELLER, J r., a citizen of the United States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Telephone- Transmitter Mouthpieces, of which the following is a full, clear, concise, and exact descriptlon.

This invention relates to telephone transmitter mouth-pieces, and the method of making them, and has for its object a mouthpiece which may be easily cleaned, and one' which will present a good appearance and be more durable and more easily manufactured than those in common use at the present time. v

The telephone mouth-pieces of hard rubber or similar compounds, which have been in common use heretofore are objectionable because they soften and lose their shape when placed in hot water to be cleaned, and also because they are easily broken or chipped in service. Those made of porcelain or a similar substance which are screwed directly -into the face plate of the telephone ltransmitter or into an adapter which is screwed or otherwise fastened to the transmitter face, have failed to meet service requirements satisfactorily, since the threads are difficult to mold with accuracy, and are easily broken or chipped, the broken parts therefrom often wedging against the transmitter diaphragm and interfering with the operation of the transmitter. Moreover, mouth-pieces in which a body portion of porcelain or similar material is held to the transmitter face plate by a screw threaded metal ferrule or adapter, to which the porcelain is cemented, have been found to be unsatisfactory not only because of the cost of providing a suitable construction, but also because of the diliiculty of procuring a cement which will not dissolve or lose its adhesive properties in boiling water. Moreover, difficulty has been experienced in obtaining a cement which docs not harden to such an extent that the structure is substantially rigid, resulting` in a high percentage of chipped or broken mouth-pieces under ordinary service conditions.

In order to eliminate the above objections, this invention provides a telephone mouthpiece having a body member of porcelain or similar substance secured to an adapter or ferrule, one end of which is threaded to screw into the front plate of a transmitter. The porcelain memberl is secured to the ferrule by means of a resilient adhesive binder, and the parts are so constructed as to provide a maximum space between the porcelain'and the ferrule for the binder, thereby making the structure less rigid and reducing the danger of breakage to a minimum. More specifically this invention provides a mouth-piece in which a metal ferrule is provided with inwardly extending lugs adapted to engage external rojections or threads in the body member o porcelain or similar substance, the parts then being held in locked engagement by means of vulcanized rubber. The use of a ferrule having inwardly extending lugs is much to be preferred over the use of a ferrule inwardly threaded, not only because of the lower cost of manufacture, but also because of the better anchorage 0btainablefor the binder, and the greater amount of this resilient material available to take up shocks and prevent breakage.

The several features of this invention may be more readily understood byA referring to the accompanying drawings, in which Figure 1 shows the assembled structure partly in section; Fig. 2 shows the construction of the porcelain body member; and Fig. 3 the metal ferrule, by meansof which the mouth-piece is fastened to the transmitter face plate. Y

The body portion 5, ofthe usual funnel shape, and preferably of porcelain, is provided at its base with a contracted portion 6, which in turn is provided with external threads 7, as clearly shown in Fig. 2. The adapter or ferrule 8 comprises a metal ring having an enlarged portion 9, and a contracted portion 10. The contracted portion is outwardly threaded to fit into the face plate of a telephone transmitter (not shown). The enlarged portion 9 is provided with indentations 11 projecting inwardly, and adapted to engage the threads of the porcelain body member. The inner surface of the enlarged portion 9 is roughened by some method, such as knurling, to increase the adhesion between such surface and the' binder 12. As a further aid in securing this binder to the porcelain body member, one or more short sections of the thread are removed, leaving spaces 13 into which the binder extends and locks the parts together.

rotary motion between the fel-rule and the pressed into place by imparting a relative Y porcelain body member, causing the projections or lugs in the 'ferrule toV engage the threads oit' the porcelain member and draw the tivoparts together. The assembled structure is then placed in an oven and kept at a temperature of approximately 1Y0 degrees centigrade for one or tivo hours to vulcanize the rubber. This process forms a resilient adhesive binder, securely iastening the porcelain member and ferrule together.

The structure is very easily assembled and may be very easily cleaned in boiling` water Without looseningthe parts. The inwardly extending lugs in the ferrule provide a means for fastening the parts together which is cheap to manufacture and one which does not mar the appearance of the completed structure.

iency of the rubber after vulcanization is sufficient to allow it to absorb shocks resulting from rough usage of the mouthpiece,v

with a minimum danger of breakage.

Vhat` is claimed is:

l. A telephone transmitter mouth-piece comprising a body member having external threads at one end, a ferrule having internal projections engaging said external threads, and a binder holding the body portion and ferrule together.

2. A telephone transmitter mouth-piece comprising a body member having external threads at one end, a ferrule having internal projections engaging said external threads, and a resilient adhesive binder holding the bodyA portion and terrule together.

3. A telephone transmitter mouth-piece comprising a body member having external projections at one end, a terrule having in- Moreover, the resilternal projections engaging Ysaid external threads, and a resilient adhesive binder holding the body portion and ferrule together.v

4. A telephone transmitter mouth-piece comprising a body member having external threads at its one end, an attaching ferrule provided with projections extending Vinwardly and adapted to engage said threads, and a resilient adhesive binder for securing said body member and said errule together.

5. A telephone transmitter mouth-piece, comprising a porcelain body member provided at one end With external threads, a ferrule for attaching said body member to a transmitter, said iferrule being provided with projections extending inwardly to engage said threads, and an adhesive resilient binder for securing said body member and said errule together.

6. A telephone transmitter mouth-piece, comprising a body member having a contracted portion provided With external threads, a feriule for attaching said body member to a transmitter, said lferrule being provided with projections adapted to engage said threads, and a resilient adhesive binder between said body member and said ferrule.

7. A telephone transmitter mouthpiece, comprising a body member having a contracted portion 'provided with external threads Which are interrupted at one or more places, a ferrule for attaching said body member to a transmitter, said errule being provided With projections adapted to engage said threads, and a resilient adhesive binder between said body member and said ferrule, said binder being anchored at the interrupted portions of said threads.

' In Witnesswhereof, I hereunto subscribe my name this 24th day of February, A. D.,

EMIL C. MUELLER, J R.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

